It's been six years since Pen Calloway watched Cat and Will, her best friends from college, walk out of her life. Through the birth of her daughter, the death of her father, and the vicissitudes of single motherhood, she has never stopped missing them. When, after years of silence, Cat--the bewitching, charismatic center of their group--urgently requests that the three meet at their college reunion, Pen can't refuse. But instead of a happy reconciliation, what awaits is a collision of past and present that sends Pen and Will on a journey around the world, with Pen's five-year-old daughter and Cat's hostile husband in tow. And as Pen and Will struggle to uncover the truth about Cat, they find more than they bargained for: startling truths about who they were before and who they are now.